Results 1 to 9 of 9

Thread: Need some help investigating rear driveline vibration after installing new gears

  1. #1
    Fresh Catch Ozon8r's Avatar
    Join Date
    Nov 2014
    Location
    Denver
    Posts
    34

    Need some help investigating rear driveline vibration after installing new gears

    I need some help solving a driveline vibration introduced with a gear install. I had a shop re-gear my Dana 44 axles to 5.13s from 4.10s and now I have a wicked driveline vibration starting at 50mph and peaks at 65mph. It is so bad that it is difficult to carry on a conversation because of the buzzing noise within the cabin and the mirrors are useless because the whole vehicle is vibrating at such a high frequency objects in the mirrors are out of focus.

    Troubleshooting has isolated the issue to my rear driveshaft or the rear differential. The tires are neither the issue nor the front driveline.

    I picked up a dial indicator and the rear shaft in front of the yoke has a 0-400th of an inch variance when rotated 360 degrees. Rotating the shaft in the yoke yield the same results, but on opposite sides of the shaft. Is this normal? Does it indicate that the yoke or pinion are not running true or that they are bent? While this may have been a pre-existing condition, it certain only became apparent after installing the new gears.

    I also measured the front of the rear ds next to the t-case yoke and the variation was 1/100th of an in and did not change when flipping 180 degrees in the yoke.

    I am not sure I’m doing the measurement right. I posted a video of how I took the measurements here:

    https://youtu.be/6T3vdXZRylw

    Some background…

    I picked up the jk a week ago Friday from the shop after re-gearing to 5.13s and immediate noticed a driveline vibration starting at 50mph and peaking at 65mph. The last time I experienced a similar issue was when I bent a rear shaft on Holy Cross trail. I didn't quite understand what was going on with the Jeep not having an issue with the 1310 aftermarket shaft since install 9 months prior. The Jeep was running fine just a little slower with 37s on 4.10 gears, but certainly no driveline vibration. Since the day I picked it up from the shop, above 50mph, the entire jeep buzzes and my mirrors vibrate so bad I can’t focus on any objects appearing in the mirrors. Additionally, the tailgate sounds like its going to vibrate off the hinges creating a significant buzzing sound within the cabin. So, I immediately assumed it was the gears and called the shop to see if this was normal and part of the break in process. Of course they said no and to bring it back in the following Wednesday. Going back to my suspicion that my ds was bent or out of balance, I spent the weekend troubleshooting. First I dropped the front ds and no change, vibration remained. Next, I dropped the rear and the vibration went away and in my mind eliminated any issue with the tires or the front end. I also checked engine and tranny mounts, dropped into neutral during the vibration, and revved the engine in neutral at a stop to see if there was any relationship to rpm. Nothing of interest.

    Monday I took the ds in for balancing at the shop that built the shaft for me. It was in balance. The jeep was vibration free while the rear shaft was off running in 4high on just the front ds.

    I dropped the Jeep off with the shop on Wednesday so they could investigate. They called on Thursday and informed me that by rotating the tires, they moved the issue to the front and suggested I have the tires balanced. However, the frequency was too high to ever be a tire issue and I know what tires out of balance do and how a vehicle feels. And when I picked up the Jeep, the vibration was still there in the seat of the Jeep and not in the steering, same as before. Again, dropping the rear shaft and the vibration stopped. But just for grins, I had a friend loan me stock tires that were well balanced. An interesting ride for sure with 5.13s, but even revving out the engine running 60mph, the vibration was still there with the rear ds reinstalled. I am absolutely certain the tires are not related.

    I've spent 40+ hours researching this issue and talked with a guy who had a similar experience after upgrading to 4.88s. Turns out he had a bad inner pinion bearing in the master install kit. Of course the shop blamed the tires as well until they finally gave in and opened up the diff.

    Appreciate any help I can get.

    Thanks
    Last edited by Ozon8r; 05-23-2016 at 03:53 AM.

  2. #2
    Meme King WJCO's Avatar
    Join Date
    Sep 2015
    Location
    Colorado
    Posts
    28,817
    Boy, it sounds like you've taken the right steps. As far as your dial indicator readings, it's usually thousands of an inch, not hundreds. The dial did seem to move a lot, but truthfully, I can't remember the last time I checked a drive shaft with that method. I would recommend if you can safely run the Jeep on jackstands or on a lift/hoist and get it up to 50mph and visually look for where the vibration is coming from. You could also do a run out test on your rear axle flanges just to make sure they aren't bent. Most manufacturers allow no more than .002 at the flange on the shaft, just make sure it's really clean and free of rust and that the dial doesn't hit the studs as you rotate it.
    Jeep parts and accessories purchased through the following link will help support this forum and at no cost to you.
    RECOMMENDED JEEP PARTS & ACCESSORIES



    Support the JL forum: JLWRANGLER.COM

    Jeep JT GLADIATOR FORUM: www.JT-Gladiator.com

  3. #3
    Knows a Thing or Two Evil's Avatar
    Join Date
    Nov 2015
    Location
    Nevada
    Posts
    705
    Do you have another shop that can verify that the yoke on the pinion side is correctly torqued? Can you drop the shaft and see how much play is in the pinion by pulling on it and pushing on it?

  4. #4
    Fresh Catch Ozon8r's Avatar
    Join Date
    Nov 2014
    Location
    Denver
    Posts
    34
    Quote Originally Posted by WJCO View Post
    Boy, it sounds like you've taken the right steps. As far as your dial indicator readings, it's usually thousands of an inch, not hundreds. The dial did seem to move a lot, but truthfully, I can't remember the last time I checked a drive shaft with that method. I would recommend if you can safely run the Jeep on jackstands or on a lift/hoist and get it up to 50mph and visually look for where the vibration is coming from. You could also do a run out test on your rear axle flanges just to make sure they aren't bent. Most manufacturers allow no more than .002 at the flange on the shaft, just make sure it's really clean and free of rust and that the dial doesn't hit the studs as you rotate it.
    Thanks for the tip. I'm taking the ds to have the shaft, u joints, and yoke inspected tomorrow. If those check out clean, I will pull the tires and check the axle flanges which are new as well (G2) and maybe another variable causing the vibration. Fix one thing, break two. It's a jeep thing .

    Quote Originally Posted by Evil View Post
    Do you have another shop that can verify that the yoke on the pinion side is correctly torqued? Can you drop the shaft and see how much play is in the pinion by pulling on it and pushing on it?
    I've already talked with another shop and gave them the history. Hopefully, it doesn't come to that. There is no play in the yoke thankfully and the shop that did the gears are highly regarded. So, I expect that torque and crush sleeve with preload are within specs given the experience of the shop. But, who knows? There could be a new tech cutting his teeth and I am bearing the burden of inexperience.
    Last edited by Ozon8r; 05-23-2016 at 03:59 AM.

  5. #5
    Administrator wayoflife's Avatar
    Join Date
    Oct 2011
    Location
    Carson City, NV
    Posts
    53,701
    Have you tried removing your FRONT drive shaft and drive around to see if you still have the vibration? Typically, that's where a new vibration will come from after installing new gears with a higher ratio. 5.13's will spin a shaft extremely fast and if you have too much caster, your front shaft will vibrate.

  6. #6
    Meme King WJCO's Avatar
    Join Date
    Sep 2015
    Location
    Colorado
    Posts
    28,817
    Quote Originally Posted by wayoflife View Post
    Have you tried removing your FRONT drive shaft and drive around to see if you still have the vibration? Typically, that's where a new vibration will come from after installing new gears with a higher ratio. 5.13's will spin a shaft extremely fast and if you have too much caster, your front shaft will vibrate.
    Yeah he did. That was my first thought as well. It's in that large middle paragraph he posted. I'm thinking parts or workmanship issue now, but who knows.
    Jeep parts and accessories purchased through the following link will help support this forum and at no cost to you.
    RECOMMENDED JEEP PARTS & ACCESSORIES



    Support the JL forum: JLWRANGLER.COM

    Jeep JT GLADIATOR FORUM: www.JT-Gladiator.com

  7. #7
    Fresh Catch Ozon8r's Avatar
    Join Date
    Nov 2014
    Location
    Denver
    Posts
    34
    Issue resolved. Turns out the rear pinion yoke was causing the 3/100ths run out as measured on the ds just front of the yoke and hence the vibration. Replacing with a new yoke resolved the vibration. The shop put a dial indicator on the ds attached to the new yoke and confirmed the run out at less than 2/1000th, much better.

    Not sure what happened to the old yoke but no matter --- problem solved.

  8. #8
    Meme King WJCO's Avatar
    Join Date
    Sep 2015
    Location
    Colorado
    Posts
    28,817
    Quote Originally Posted by Ozon8r View Post
    Issue resolved. Turns out the rear pinion yoke was causing the 3/100ths run out as measured on the ds just front of the yoke and hence the vibration. Replacing with a new yoke resolved the vibration. The shop put a dial indicator on the ds attached to the new yoke and confirmed the run out at less than 2/1000th, much better.

    Not sure what happened to the old yoke but no matter --- problem solved.
    Very cool. And damn good that they didn't have to open up the pumpkin again and deal with that crap. Glad you got it resolved.
    Jeep parts and accessories purchased through the following link will help support this forum and at no cost to you.
    RECOMMENDED JEEP PARTS & ACCESSORIES



    Support the JL forum: JLWRANGLER.COM

    Jeep JT GLADIATOR FORUM: www.JT-Gladiator.com

  9. #9
    Been Around the Block JK07's Avatar
    Join Date
    Feb 2013
    Location
    Pennsylvania
    Posts
    392
    Thanks for sharing - I am going through a very similar situation after my 5.13 install. I will share this with my shop. Fingers crossed!
    JK07

    Rubicat

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
“wayoflife” is a moniker that I’ve been using for 20 years now and I chose it because I think it does a great job of explaining, in simple terms, the passion I have for Jeeps and the Jeep way of life. This is a lifestyle that transcends age, gender and race as the only thing you need to be a part of it is a love for the outdoors, a desire to explore, a yearning to take on a challenge and a will to conquer it. Over the years, Cindy and I have attempted to capture the essence of this lifestyle through photographs and videos and share it with others around the world. And, this is how WAYALIFE was born.
Join us
WATCH OUR VIDEOS